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Updated: Nov 24, 2025
Use of an Eight-arm Radial Water Maze to Assess Working and Reference Memory Following Neonatal Brain Injury
Published on: December 4, 2013
Effects of Juvenile or Adolescent Working Memory Experience and Inter-Alpha Inhibitor Protein Treatment after
Aaron Bradford1, Miranda Hernandez1, Elaine Kearney1
1Neuroscience Program, School of Health Sciences, Regis College, 235 Wellesley Street, Weston, MA 02493, USA.
Insights
Early cognitive interventions, like the radial water maze task, combined with Inter-alpha Inhibitor Proteins (IAIPs), can significantly improve learning and memory in neonatal hypoxic-ischemic (HI) brain injury models.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Neonatal Hypoxic-Ischemic (HI) brain injury leads to persistent cognitive deficits.
- Current diagnostic and therapeutic options for HI brain injury are limited.
- Previous research identified Inter-alpha Inhibitor Proteins (IAIPs) and early cognitive tasks as beneficial interventions.
Purpose of the Study:
- To investigate the combined effects of IAIPs and early experience in an eight-arm radial water maze (RWM) task.
- To determine optimal age windows for behavioral interventions in a rat model of HI brain injury.
- To evaluate the impact of juvenile versus adolescent RWM testing on cognitive outcomes.
Main Methods:
- Rats with HI brain injury received either vehicle or IAIPs.
- Subjects underwent RWM testing initiated at either the juvenile (P31) or adolescent (P52) stage.
- Performance was assessed through error rates in the RWM, with subsequent adult retesting.
Main Results:
- HI injury globally impaired performance compared to sham controls.
- IAIP treatment in HI subjects tested as juveniles reduced errors compared to untreated HI counterparts.
- Juvenile-initiated RWM testing led to fewer errors and improved retention compared to adolescent initiation.
Conclusions:
- Combining behavioral interventions (RWM) with anti-inflammatory treatment (IAIPs) improves cognitive function in HI brain injury.
- Early life cognitive experience represents a sensitive period for enhancing long-term learning outcomes.
- Developmentally targeted therapeutics and task-specific experiences offer promising strategies for mitigating HI-induced cognitive impairment.
Abstract:
Hypoxic-Ischemic (HI) brain injury in the neonate contributes to life-long cognitive impairment. Early diagnosis and therapeutic interventions are critical but limited. We previously reported in a rat model of HI two interventional approaches that improve cognitive and sensory function: administration of Inter-alpha Inhibitor Proteins (IAIPs) and early experience in an eight-arm radial water maze (RWM) task. Here, we expanded these studies to examine the combined effects of IAIPs and multiple weeks of RWM assessment beginning with juvenile or adolescent rats to evaluate optimal age windows for behavioral interventions. Subjects were divided into treatment groups; HI with vehicle, sham surgery with vehicle, and HI with IAIPs, and received either juvenile (P31 initiation) or adolescent (P52 initiation) RWM testing, followed by adult retesting. Error rates on the RWM decreased across weeks for all conditions. Whereas, HI injury impaired global performance as compared to shams. IAIP-treated HI subjects tested as juveniles made fewer errors as compared to their untreated HI counterparts. The juvenile group made significantly fewer errors on moderate demand trials and showed improved retention as compared to the adolescent group during the first week of adult retesting. Together, results support and extend our previous findings that combining behavioral and anti-inflammatory interventions in the presence of HI improves subsequent learning performance. Results further indicate sensitive periods for behavioral interventions to improve cognitive outcomes. Specifically, early life cognitive experience can improve long-term learning performance even in the presence of HI injury. Results from this study provide insight into typical brain development and the impact of developmentally targeted therapeutics and task-specific experience on subsequent cognitive processing.
